Nasal inhalers have been available for a number of years to permit convenient inhalation of medicaments, such as benzedrine, ephedrine, menthol and camphor, often used to relieve nasal congestion associated with the common cold. In addition, when the inhalers have satisfactory seals and are properly constructed, they are also useful in dispensing vasodialators, sometimes used to treat heart patients, such as amyl nitrite and other short-chain alkyl nitrites.
Prior art nasal inhalers range from units employed to be used in a single nostril of the nose to units which have dual protuberances to be received in both nostrils simultaneously. Inhalers representative of the dual nostril type are shown in U.S. Pat. No. 3,724,459 issued to Congro and U.S. Pat. No. 3,255,750 issued to Schwartzman et al.
Basically, inhalers, whether constructed for single or dual nostril use, most often employ a cap which is required to be removed when the inhaler is in use, thereby uncovering an inhaling protuberance of the unit that is inserted in a nostril so that, upon inhalation by the user, air flow passes through a wadding material in the inhaler having an absorbed medicament, thereby carrying its concentrated vapors into the user's nasal passages and lungs. Most of these inhalers do not have the cap retained in any manner, such as the hinged construction shown in the aforementioned Congro patent. Further, the known prior art inhalers do not have fully adjustable means to control the air flow through the unit, whereby the concentration of the vapors of the medicament in the air flow can be precisely adjusted.
In addition, the prior art units are not constructed in a manner that they can be used for the more volatile inhalants, such as ammonia and the vasodialators mentioned above. Normally, ammonia and the vasodialators are often packaged in closed glass vials which are broken just prior to use to prevent inadvertent evaporation. However, with proper construction of the inhaler, it is possible to contain these more volatile inhalants which would otherwise rapidly evaporate. Of course, to contain such volatile inhalants, it is necessary that the inhaler unit not be vented to the atmosphere when not in use and also that it have adequate seals to prevent the loss of vapor from these substances.